ML19325D978

Discusses Completion of Steam Generator Tubing Insp.Total of 4,316 Tubes Inspected & 62 Tubes Removed from Svc by Mechanical Plugging.Insp Significantly Exceeded Amount of Tubing Required to Be Inspected

ML19325D978
Person / Time
Site:	San Onofre
Issue date:	10/19/1989
From:	Morgan H SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8910300204
Download: ML19325D978 (2)

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Subject:

Docket No.' 50-361  !

'Special Report Inservice Inspection of Steam Generator Tubes San Onofre Nuclear Generating Station, Unit 2

References:

. A. 'PWR Steam ~ Generator Examination Guidelines, Revision 2,-

g Electric Power Research Institute (EPRI) Report Number  ;

NP-6201, dated December 1988.

j B. Letter from M. O. Medford (SCE) to Mr. G. W. Knighton  !

(USNRC) dated April 5, 1985. j Pursuant to Surveillance Requirement 4.4.4.5(a) of Appendix A, Technical Specifications ~to Facility Operating License NPF-10, this report is being '

submitted to the Commission following the completion of inservice inspection

p. of' steam generator tubes at San'0nofre Unit 2.  ;

Eddy current' inspection.of the steam generator tubing was completed on October .

4~, 1989. A' total of 4316 tubes (23.7% of the tubes in service) in two steam ,

H generators were inspected full length and 62 tubes were removed from service  ;

by mechanical plugging. This inspection significantly exceeded the amount of '

y tubing required to be inspected per Surveillance Requirements 4.4.4.0 through 14.4.4.2 including all prospective C-2 expansions (i.e., a 3% sample plus a 6%

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(2S)'and~a 12% (45) expansion in each steam generator).

%. t Ly The planned inspection programs for both steam generators were fully J consistent with recent industry recommendations in the "PWR Steam Generator ,

E Examination Guidelines" (Reference A). The programs included inspection of . '

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'the, full length of 100% of the tubing in the area of the tube bundle where the

, batwing wear mechanism previously described in Reference B is active. The *

' programs also included general surveillance of the full length of 20% of the W :, remainder of the tubing. The programs were expanded to include tubes adjacent

.to; or associated with tubes exhibiting new eddy current indications. ..'

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c h  ! Dociant Control' Desk October 19. 1989 i

In Steam Generator E 088, 2170 tubes were inspected. No tubes were found to be defective. ' Twenty-nine tubes were preventively plugged.due to the wear z mechanism previously described in Reference B. One tube was preventively

?u , . plugged due to degradation at a vertical strap support, a'nd one tube was t

' preventively plugged due to tie-rod' denting. -

L In Steam Generator E-089, 2146 tubes were inspected. One tube was found to be  !

l- ' defective and was plugged. . Eddy Current data indicates this tube is dented at  !

the top of the hot leg tubesheet. Notably it is. adjacent to a carbon steel tie rod. 'In steam generator E-089, fourteen tubes were preventively plugged due to the wear mechanism described in Reference B, and. sixteen tubes were m preventively plugged due to the tie-rod denting.

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[L As~ required by Surveillance Requirement 4.4.4.5(b), complete results of the

recently completed inservice inspection will be submitted to the Commission by ~

, October 3~, 1990. 1 If you require any additional information, please so advise.

Sincerely, l, &LW L

l cc: J. B. Martin (Regional Administrator, USNRC Region V)

C. W. Caldwell (USNRC Senior Resident Inspector, Units 1, 2 & 3)

L. Kokajko (Project Manager, SONGS 2/3, USNRC, NRR) t Institute of Nuclear Power Operations (INPO) ~

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